Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012833 (dizziness)
 9,689 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bepridil, a calcium antagonist with a half-life of approximately 42 hours, was compared with placebo in a double-blind, randomized, crossover trial. Thirteen men (average age 62 years) with exercise-related angina pectoris and a positive exercise test (modified Bruce protocol) were studied. In the group as a whole, bepridil (400 mg once a day) caused an increased total exercise time (2.6 +/- 1.8 minutes, mean +/- standard deviation), time to onset of angina (3.3 +/- 1.6 minutes), time to 1 mm of ST-segment depression (2.2 +/- 2.3 minutes), time to 2 mm of ST-segment depression (2.4 +/- 1.4 minutes) and total work load achieved (1.8 +/- 1.4 kpm) compared with the preceding placebo phase (all p less than 0.05). Frequency of angina and nitroglycerin consumption were low and did not change significantly during bepridil therapy. Comparison of the 3 placebo periods (run-in, double-blind and washout) did not reveal a change in any measurement except time to onset of angina, suggesting no training effect or change in patient status. Adverse effects were common in patients taking both placebo and bepridil, but only 2 patients had adverse effects (dizziness) with bepridil that necessitated discontinuation of therapy. Similarity of the double product (systolic blood pressure X heart rate) at the end of exercise suggests a decrease in myocardial oxygen demand as the primary mode of action. This study suggests that bepridil is a promising agent for the treatment of exercise-induced myocardial ischemia.
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PMID:Effects of bepridil on exercise tolerance in chronic stable angina: a double-blind, randomized, placebo-controlled, crossover trial. 636 14

The authors review the existing literature on inhalation of gasoline fumes, highlighting the acute and chronic physical and psychological effects. The clinical picture of gas sniffing includes visual hallucinations, changes in consciousness, euphoria, nystagmus, dizziness, weakness and tremors. There is the possibility of rapid recovery, sudden death or brain damage with chronic abuse. When leaded gasoline is abused then blood and urine lead levels and erythrocytic delta-aminolevulinic acid dehydrase (ALAD) levels may be helpful. Although the treatment of acute and chronic gas sniffing syndromes is often supportive and non-specific, when lead levels are high chelated therapy is indicated including British anti-lewisite, calcium disodium versenate or D-penicillamine. We also report our findings on an isolated native Indian population where intentional gas sniffing has reached epidemic proportions. Ten percent of the total population and 25% of the children between 5 and 15 years of age had been identified as gasoline inhalation abusers. In this population, the most important etiological factors included environmental, family and cultural components. The authors emphasize the need to correct the family and social deficiencies in such communities if the incidence of gas sniffing is to be decreased.
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PMID:Gas sniffing as a form of substance abuse. 670 83

Verapamil hydrochloride, a prototype calcium antagonist, is now marketed in the United States for the acute treatment of supraventricular tachyarrhythmias and for chronic management of vasospastic and chronic stable angina. It inhibits the slow inward channel in in the heart and blocks calcium influx in smooth muscle. Its intrinsic negative inotropic action, which is apparent in isolated tissues, is offset in vivo by peripheral vasodilation. It has a mild, noncompetitive sympathetic antagonist effect; its most important electrophysiologic action is a depression of AV nodal conduction, accounting for its effect in supraventricular tachyarrhythmias. Its hemodynamic actions are characterized by a complex interplay of changes in preload, afterload, contractility, heart rate, and coronary blood flow. It does not depress cardiac function, except in severe heart failure. The drug has a mild dilator action on coronary arteries and reverses ergonovine-induced vasoconstriction. Controlled trials have established its role in Prinzmetal's variant angina, unstable angina, and chronic stable angina. It has also been found to be effective in obstructive cardiomyopathies. The potential role of verapamil in such conditions as hypertension, cardioprotection, and Raynaud's phenomenon needs further evaluation; at present these indications have not been approved by the Food and Drug Administration. The most common side effects include constipation, skin rash, and dizziness; AV block, heart failure, and sinus arrest may occasionally be encountered, especially when ventricular function is compromised or conduction system disease is present.
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PMID:Verapamil hydrochloride: pharmacological properties and role in cardiovascular therapeutics. 676 30

A 68-year-old female on two-year chronic hemodialysis for chronic renal failure due to chronic pyelonephritis, was admitted to hospital for weakness, dulled sensorium and dizziness. On examination the patient was in a state of circulatory collapse, the electrocardiogram showed an accelerated idioventricular rhythm and laboratory analysis revealed extreme hyperkalemia (K+ 10.1 mmol/l). There were no common causes of shock, such as hypovolemia, sepsis, heart failure and presence of vasodilator drugs. The patient was treated with calcium gluconate, sodium bicarbonate and sodium chloride (to oppose the effects of hyperkalemia on the cell membrane to minimize cardiac and neuromuscular toxicity), insulin and dextrose (to increase the transport of K+ from the extracellular to the intracellular compartment), and hemodialysis (to remove K+ from the body). At the end of the hemodialysis session, the patient was in a clinically good condition, blood pressure was 160/90 mm Hg and the serum K+ concentration was normal. The case appeared to suggest that extreme hyperkalemia may have direct effects on vascular resistance, causing hypotension and shock.
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PMID:A life-threatening complication of extreme hyperkalemia in a patient on maintenance hemodialysis. 748 41

Mibefradil (Ro 40-5967) is a novel calcium antagonist from a new chemical class and is the first that selectively blocks the T-type calcium channel. In this multicenter, double-blind, placebo-controlled, parallel designed study, its antianginal and antiischemic effects were evaluated in 126 patients with chronic stable angina pectoris. Exercise tests were performed after 1 week of placebo (baseline) and 2 weeks after randomization to 25, 50, 100, and 150 mg (once daily) or placebo. Highly significant dose-response relations were present across all treatment groups for exercise duration, time to angina, and time to ST-segment depression. They were associated with a dose-dependent decrease in heart rate and blood pressure and plasma concentrations > 300 ng/ml. Mibefradil was well tolerated. First-degree atrioventricular block (8%) and dizziness (7%) were the most frequently reported adverse events; however, the first-degree atrioventricular block was dose-related, and only one patient discontinued the trial because of dizziness. The excellent efficacy and adequate safety profile of mibefradil may be a consequence of T-type calcium-channel selectivity.
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PMID:Effects of the new calcium antagonist mibefradil (Ro 40-5967) on exercise duration in patients with chronic stable angina pectoris: a multicenter, placebo-controlled study. Ro 40-5967 International Study Group. 757 82

A 50-year-old very obese man had suffered from hypertension for more than 20 years and had undergone various treatment regimens, the last being with an ACE inhibitor. Since his hypertension had nevertheless increased, and he developed dizziness and headaches, a combination of ACE-inhibitor and calcium antagonist was now tried, followed--when this treatment proved unsuccessful--by the fixed-combination preparation containing enalapril plus hydrochlorothiazide. This at last led to a reduction in his blood pressure to approaching normal values, and his subjective symptoms cleared up.
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PMID:[Lowering blood pressure in an obese patient with long-term hypertension. Using a fixed combination of enalapril/hydrochlorothiazide]. 760 92

It is still not established whether or not glucocorticoids are effective in the treatment of vestibular disorders such as dizziness and imbalance, although these drugs in combination with several others are used to treat dizziness and imbalance in some diseases. This study was undertaken to investigate the effects of a glucocorticoid, dexamethasone, on vestibular disorder following unilateral labyrinthectomy in pigmented rabbits. Neuronal activities of the medial vestibular nucleus (MVN) in alpha-chloralose-anesthetized cats were also investigated. Systemic injection of dexamethasone decreased the frequency of nystagmus and head deviation dose-dependently following hemilabyrinthectomy, and the rate of decrease was faster than that obtained by saline. In contrast, RU38486 (a glucocorticoid receptor antagonist) delayed the reduction of nystagmus and head deviation. Micro-iontophoretic application of dexamethasone rapidly enhanced the spontaneous firing of MVN neurons in a dose-dependent manner. These increases were blocked by RU38486, but not by GDEE (a glutamate receptor antagonist) or Co2+ (a Ca2+ channel blocker). These results suggest that dexamethasone directly activates the MVN neurons, thereby accelerating vestibular compensation.
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PMID:Role of glucocorticoid in vestibular compensation in relation to activation of vestibular nucleus neurons. 761 Aug 57

The results of an open prospective study that evaluated the long-term clinical safety of nicorandil are presented. This study included 199 patients with severe chronic stable angina treated over a 1-year period. The most often reported adverse event was headache, which was responsible for most of the study withdrawals due to clinical intolerance (9.6%). When using a progressive titration scheme, this incidence was substantially reduced to 2.7%. As with other less frequent adverse events (dizziness, gastrointestinal disorders), headaches were reported as being mild to moderate in severity, were experienced during the first days of treatment, and, if treatment was maintained, usually resolved within a few days. The incidence of adverse events was not modified when nicorandil was given in combination with a beta-blocker, a calcium antagonist, or both agents. Cardiovascular safety was satisfactory and laboratory parameters were not altered. At the end of the study, 70% of patients were maintained on nicorandil. These results are in agreement with those reported from the nicorandil safety database, which gathered 1152 patients treated by nicorandil, including those of the present study. In comparative studies of nicorandil versus beta-blockers, calcium antagonists, or nitrates, the overall incidence of adverse events was no different between the two treatment groups, although the safety profile differed according to the drug category.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nicorandil safety in the long-term treatment of coronary heart disease. 764 28

EFFECTS OF SHORTER-ACTING CALCIUM ANTAGONISTS: The antihypertensive effect of the dihydropyridine calcium antagonists is highly correlated with the drug plasma concentration. These agents reduce blood pressure primarily via arteriolar vasodilation. More rapidly absorbed formulations such as the nifedipine capsule quickly produce a marked fall in blood pressure which tends to provoke a reflex increase in sympathetic nervous activity via the baroreceptor mechanism. These shorter-acting formulations are therefore more likely to be associated with vasodilatory side-effects such as flushing, palpitations, ankle edema, headaches and dizziness. ADVANTAGES OF LONGER-ACTING AGENTS: The link between pharmacokinetics, pharmacodynamics and side effects becomes more evident when longer-acting agents such as nifedipine gastrointestinal therapeutic system (GITS) and amlodipine are examined. These drugs have a trough: peak ratio that approaches 1, and thus exert a uniform antihypertensive effect over the dose interval. They are associated with fewer side effects in consequence of less baroreceptor reflex stimulation. The net result is improved efficacy and greater patient tolerability of these compounds.
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PMID:Dihydropyridine calcium antagonists and the trough: peak ratio: focus on adverse effects. 770 60

A great number of calcium antagonists are available for the treatment of cardiovascular diseases. Differences in pharmacodynamic and/or pharmacokinetic properties can be used to optimize therapy in patients and to minimize side effects. In contrast to all dihydropyridine (DHP) derivatives, drugs of the verapamil type slow atrioventricular conduction and are widely used for treatment of supraventricular tachycardia. The higher vasoselectivity of new DHP derivatives as compared with nifedipine should be regarded as an advantage for the treatment of patients with impaired left ventricular function. Besides vasodilation, additional effects such as antiatherosclerotic action, amelioration of rheological parameters, bronchial relaxation, or improvement of cerebral capacity in patients with cerebro-organic disorders have been documented for individual drugs. The long plasma half-life of some new calcium antagonists is advantageous with respect to patient compliance. Furthermore, a delayed increase in plasma concentration (high tmax values) is useful to minimize side effects such as reflex tachycardia, flush, headache, and dizziness.
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PMID:Calcium antagonists in comparison: view of the pharmacologist. 789


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